Stereopsis is the process by which the human brain interprets an object's depth based on the relative displacement of the object as seen from the left and right eyes. The stereoscopic effect may be artificially induced by taking first and second images of a scene from first and second laterally offset viewing positions and presenting the images separately to each of the left and right eyes. By capturing a succession of stereoscopic image pairs in time, the image pairs may be successively presented to the eyes to form a stereoscopic movie that appears to the user as having three-dimensions.
Two traditional cameras may be used to acquire each of the images of a stereoscopic image pair. A traditional camera may be properly focused using an autofocus procedure which captures a plurality of images at different focal depths. The focal depth corresponding to the highest frequency content is then used for subsequent image captures. Traditional movie cameras may use this method to autofocus during video capture. However, the capture of frames will need to be periodically delayed while the autofocus functionality is performed.
While suitable for capturing 2D images with a single traditional camera, this autofocus technique may be unsuitable for stereoscopic image capture. In particular, the technique may disrupt the video stream and may be affected by camera movement, such as by the user's hand motions.